1. Field of the Invention
This invention relates to a molding apparatus and more particularly to a molding apparatus for forming an insulating, moisture resistant, resilient polymeric coating on the surface of an irregularly sized article.
2. Description of the Prior Art
In the art of conduit connectors, such as fittings, coupling devices and the like having threaded end portions to which conduits are secured and thereby joined with the connector, it is often desirable to coat the connector and a portion of the conduits with an insulating and moisture resistant material such as a polyvinylchloride (PVC) film. In many field applications the members are subjected to a corrosive environment where moisture can easily enter into a conduit connector. Furthermore, corrosive stray currents might pass through the conduit to the connector. Thus, an insulating and moisture resistant coating applied to the connector is necessary to protect the connector against galvanic and chemical corrosion.
Difficulties are encountered in applying an effective insulating, moisture resistant seal to a connector prior to installation. Subsequently, the seal must be effected after installation which initially exposes the connector and conduits to the corrosive atmosphere permitting moisture and dirt to enter into the connector and on the threaded ends of the connector and conduit. In many applications it is necessary to disassemble the conduits from the connector; and if a seal is formed on the members after assembly, the seal must be broken and reapplied. This procedure further exposes the connector and conduits to corrosive damage.
Power-coating and mold coating insulating, moisture resistant linings on conduit connectors have been suggested. In this manner, flange portions formed by end portions of the lining extend beyond the ends of the connector and flare outwardly. The conduits are threadedly advanced onto the ends of the connector and into contact with the flange portions to effect a fluid-tight seal between the connector and conduits. However, the connectors may vary in the size of the threaded end portions within the range of commercial connector tolerances. Therefore, it is difficult to provide a standard mold which can accommodate the range of tolerances that may occur to form an insulating, moisture resistant coating on the connector.
There is need for molding apparatus to form an insulating, moisture resistant coating on the surface of a conduit connector having threaded end portions which may vary in length within commercial tolerances to effect an insulating, moisture resistant seal between the connector and conduit members threadedly engaged thereto.